A control rod for a nuclear reactor is known, which contains a series of pivotally connected links containing a neutron absorbing material and having a means for the collection of the gas produced as a result of the absorption of neutrons by said material.
In said known control rod, the neutron absorbing material only partially occupies the volume of each link. The rest of the volume serves as the means for the collection of the gas, which is necessary to reduce the value of the pressure of the gas acting from the inside onto the sheath of the link. The presence of free spaces in each link results in an overall reduction of the amount of the neutron absorbing material that can be carried by the control rod, and, hence, affects the efficiency of said rod. The service life of this rod is limited by the time during which the pressure of the gas within the link is built up to a critical value (from the point of view of the strength of the sheath of the link). Thus, with the control rod being of the above-described known structure, its service life can be prolonged by increasing the free space in each link, and the overall efficiency of the rod is reduced as a result, and vice versa.